In the prior art, resin bolting systems have been employed where it was necessary to securely fix a bolt into a hole previously drilled in a hard substrate, such as rock or concrete. It has been found that purely mechanical bolting gave rise to certain problems such as insecure or unstable bolting, as well as possible pilferage of the bolt. More particularly, when a mechanical bolt is placed into rock or cement, crumbling of the substrate around the bolt will cause the bolt to loosen and possibly fall out. In addition, mechanical bolts are susceptible to pilferage in that they can be unscrewed and removed.
To remedy these problems, resin bolting systems were developed wherein a polyester resin mixed with a catalyst is pumped into a pre-drilled hole whereupon a bolt is inserted before the polyester resin has fully cured. By this method, the bolt is permanently affixed in the substrate thereby preventing pilferage. In addition, the polyester resin fills in the cracks in the bolt hole and stabilizes the frangible walls of the hole so that the bolt is provided with a secure, rigid and permanent support.
The process of mixing a combination of a polyester resin and a catalyst in the required proportions and thereafter pumping the composition into a hole is both difficult and time-consuming. To obviate these shortcomings, prior art devices have been developed wherein a resin and a catalyst are placed in a capsule in fixed amounts. One of these capsules may then be placed in a bolt hole at the time when the bolting is to take place. The subsequent insertion of the bolt funtions to rupture the filled capsule such that the catalyst and the resin are mixed to form the hardened composition for securing the bolt. It has been found that rotation of the bolt simultaneous with its insertion into the bolt hole insures that the catalyst and the resin become fully mixed.
Examples of the resin capsules used in the prior art include U.S. Pat. No. 3,737,027 to Ball and U.S. Pat. No. 3,861,522 to Llewellyn et al. The former patent discloses a two component hardening resin system which comprises two flexible frangible containers, one which is disposed entirely within the other. In this system, a catalyst, the generally smaller component, is placed in a frangible tube. A larger frangible tube, which entirely surrounds the inner tube holding the catalyst, is filled with a polyester resin. This entire assembly may then be inserted into a bolt hole so that when the bolt is inserted and rotated, it will rupture the frangible walls of the container allowing the resin and catalyst to mix thereby forming the hardening resin system.
In contrast, U.S. Pat. No. 3,861,522 to Llewellyn discloses a resin system wherein a tubular, compartmented package has a flexible divider wall therein. The divider wall separates the tubular package into two compartments such that the resin may be placed into one compartment and the catalyst placed into the other compartment. As in U.S. Pat. No. 3,737,027 to Ball, the entire tube is then placed into the bolt hole followed by the insertion of the bolt. The bolt ruptures the walls of the container enabling the resin and the catalyst to mix such that the resin will cure forming a secure bolting system.
The above described resin bolting systems are used primarily in mine roof bolting, wherein bolt holes are drilled having a diameter of generally one to two inches. However, when the bolt hole is to be less than half an inch in diameter, it becomes unfeasible to use a complex compartment within a compartment resin bolting package. Typical of an application wherein the bolt hole has a relatively small diameter is the installation of a safety reflector in a cement structure such as a bridge abutment, post, or a highway center divider. More particularly, when installing bolts for highway safety reflectors, bolt holes of only 5/16 of an inch in diameter and having a depth of approximately 21/2 inches are used, such that the cost of producing a compartment within a compartment resin package becomes prohibitive.
Therefore, it is an object of the subject invention to provide a parallel tube resin package for use in conjunction with bolt holes having a relatively small diameter and short depth.
It is a further object of the subject invention to provide a parallel tube resin package which is both economical to produce and easy to use.